The areas that will cause concern for the test taker will most likely be the wide array of topics that you must know for this exam. You will need to be a Jack-of-all-trades, in that you must know a variety of topics and know then pretty well. The two messaging applications could cause trouble if you’re not paying close attention to the question. While CUC and CUE have similar characteristics, they also have subtle differences that could be exploited on an exam. The areas you will probably need to know include handlers, dial plan, and distribution list. You will need to know them both and know them well.
The Presence sections of the test could cause issues if you’re not familiar with it, since there are quite a few companies that haven’t implemented a full presence solution. You’ll need to make sure that all the configuration options are in your study plans.
VPIM is another area were the test taker might run into trouble, VPIM might not be used in your companies Unified Communications environment. This will mean you’ll have to find some way to get hands on experience before attempting the exam.